Non-invasive electrogastrography. Part 2. Human electrogastrogram

The electrical activity of human stomach muscle wall-electrogastrogram (EGG), was led off by surface (cutaneous) electrodes placed on the abdominal wall and recorded on an electrogastrograph. A method for complete elimination of the cardiac artefact was elaborated and successfully implemented. It consists of a preliminary elimination of the QRS complex, based on its higher amplitude and slope. The eliminated intervals were replaced by linear segments. A subsequent low-pass filtering allowed to obtain a high quality EGG signal. The electrical activity of the stomach of healthy volunteers was characterized by waves with a frequency of 3.35 +/- 0.09 cpm during the quiescent periods and 2.99 +/- 0.14 cpm during the activity periods of the migrating myoelectrical complex (MMC). Bearing in mind the correlation between the bursts of spike potentials with the slow waves in the dog EGMG and the high-amplitude waves, characterizing the periods of activity in the dog EGG, we can better differentiate the periods of quiescence and activity by the amplitude of the waves. The wave amplitude during periods of quiescence was 81.13 +/- 20.61 microV, significantly different from the wave amplitude during periods of activity being 164.74 +/- 43.34 microV (n = 7). Thus with this method in visual inspection it is possible to identify MMC of the human stomach by the changes in the amplitude of the waves in the EGG.